Why exactly do women show skin?

Excuse me for raising this question. But this is my sheer curiosity after over a basic question after reading an article about skin show in women.
A team of scientists decided to find out exactly how much skin a woman should show if she wants to attract a man. They had assigned some 10% for each hand and a 15% for each leg etc. and they are calling the 40% er the "Optimal Woman". Why? ...because reasearch shows Any less skin than that and men pass by the woman for someone who is willing to show more. Again, women who showed more than 40%, were also passed on by men. Experts believe that showing too much flesh puts men off because it suggests they might be unfaithful. Well, thanks for the info.

 I was wondering over another issue. Most women do not admit that they show skin to attract men. If they are telling the truth what other reasons could be it?